Converting Sketch to Library- Initialization of array not being seen

Hello! I am implementing a library and decided to first write it as a sketch where everything works fine. However, when I moved everything over to a .h and .cpp file, I come across a declaration error… I don’t think I am doing it in the right place, but nothing I have tried seems to work. Can anyone point me in the right direction?

I have replicated this issue in a simplified version of my library. If anyone is feeling kind, you would just need to throw this folder in your custom library folder and run the example sketch. (6.63 KB)

Figured it out. I had a class member array that a non-member function (the ISR) was trying to access, so I just moved my array outside of the class and made it static in the implementation file.